Question Change CSC S21 ultra

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mpore14

Senior Member
Jul 25, 2012
205
86
Samsung Galaxy S21 Ultra
-Connect the phone to the PC and install the Samsung driver if you have not yet installed
-Activate USB debugging (Click Accept USB debugging on the phone if it appears)
-type *#0*#
-Change CSC (beta) (write CSC THL, DBT, BTU....)
-Change CSC (beta) - one click
-Reboot manually
View attachment 5643601
Is this legit? Does this trip knox? I couldn't find any other forums that use this.
 

bntnja

Senior Member
Oct 27, 2013
66
60
it works for me, but I have to press Change CSC button for 3 times to work.
 

ser8210

Senior Member
May 16, 2010
61
64
Samsung Galaxy S21 Ultra
Is this legit? Does this trip knox? I couldn't find any other forums that use this.
Hi.

This app does not break the knox.

Maybe it's not in many forums because the csc change still has limitations like some devices don't respond to the *#0*# code and others don't have the right csc, for example to get call recording, which is its most widespread use .
For the change of csc, the program uses an old acquaintance that is none other than the sending of certain AT+ commands that, out of respect for the developers, I will not publish.

There are many AT+ codes and examples on the Internet.
I seem to remember that there is a thread here on xda that talks about it.

Some people say that the commands used by the program come from the Samsung leak published by lapus$, but it is not clear.
I found some references in the leak, but I don't have time to search 200gb for those specific commands.

I didn't find anything strange in the program but since I don't have the source code I didn't search everything it contains, I just focused on the method it uses to change the csc and something else, I used reverse engineering and just out of curiosity.

Salu2
 

mpore14

Senior Member
Jul 25, 2012
205
86
Samsung Galaxy S21 Ultra
Hi.

This app does not break the knox.

Maybe it's not in many forums because the csc change still has limitations like some devices don't respond to the *#0*# code and others don't have the right csc, for example to get call recording, which is its most widespread use .
For the change of csc, the program uses an old acquaintance that is none other than the sending of certain AT+ commands that, out of respect for the developers, I will not publish.

There are many AT+ codes and examples on the Internet.
I seem to remember that there is a thread here on xda that talks about it.

Some people say that the commands used by the program come from the Samsung leak published by lapus$, but it is not clear.
I found some references in the leak, but I don't have time to search 200gb for those specific commands.

I didn't find anything strange in the program but since I don't have the source code I didn't search everything it contains, I just focused on the method it uses to change the csc and something else, I used reverse engineering and just out of curiosity.

Salu2
Hey Salu2,

Thanks so much for your reply. Appreciate it.

Us at G9980 thread wonders why it's impossible to switch between TGY and BRI. Maybe this would help.

Also, it's interesting to know that Samsung had those leaks.

Cheers
 
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ser8210

Senior Member
May 16, 2010
61
64
Samsung Galaxy S21 Ultra
Hey Salu2,

Thanks so much for your reply. Appreciate it.

Us at G9980 thread wonders why it's impossible to switch between TGY and BRI. Maybe this would help.

Also, it's interesting to know that Samsung had those leaks.

Cheers
Hi.

The problem may be due to these csc being unique.

That is, for example the csc dbt is part of a multi csc firmware so it contains a large number of csc and you can switch between them.

Other regions are of a single csc code and that is why it does not allow to make the change.

Salu2
 

bntnja

Senior Member
Oct 27, 2013
66
60
You tried 1 time, 2 times and 3 times or you tried 3 times at first, and any change when it success before you restart your phone?
This is what I did
"
It finally works!
I clicked "change csc (beta)" button for 3 times for it to work, the 2nd time, I notice it has FT Mode in the notification bar, and then I press that change csc button again. and tada! SEK
"
Just press 3 times in a row, and restart. it works for me.
 

hisoka78

Member
Oct 14, 2012
28
2
-Connect the phone to the PC and install the Samsung driver if you have not yet installed
-Activate USB debugging (Click Accept USB debugging on the phone if it appears)
-type *#0*#
-Change CSC (beta) (write CSC THL, DBT, BTU....)
-Change CSC (beta) - one click
-Reboot manually
View attachment 5643601

I did this on my S21 Ultra 3 times on a row and i used EGY CSC and it's works.

Thanks
 

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minhnewpro

Senior Member
Dec 6, 2014
938
284
25
Hải Dương
This is what I did
"
It finally works!
I clicked "change csc (beta)" button for 3 times for it to work, the 2nd time, I notice it has FT Mode in the notification bar, and then I press that change csc button again. and tada! SEK
"
Just press 3 times in a row, and restart. it works for me.
Hmm, seem S21 Ultra Korean cannot change CSC for now. I tried 3 times or even 4 times, notthing change after restart
 

bodomfan

Senior Member
Mar 9, 2011
7,370
4,340
36
Swansea
Worked in the end
 

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d33dvb

Senior Member
Found an easy way to change CSC.

On your phone, open samsung dialer, type *#0*#
Enable ADB debugging
Connect the USB
Open FRP tool, type in your csc and click change csc.


Edit: posted before reading the last page, my bad, i thought i had stumbled upon a solution, doh
 

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  • 2
    Hi.

    Activation for verizon doesn't work in the latest version?
    I don't have that model but in the changelog it says that you can activate the function again.

    Big Update v.3.0 12/7/2022

    - Add [MTP] Enable secret code (*#06#, *#0*#,...) for Verizon phone
    - Add [TestMode] Disable Factory mode
    - Fix [MTP] Read information: show FAIL on some device
    - Fix [DLM] Read information: a small error
    - Improve [TestMode] Change CSC
    - Improve [ADB] Get list supported CSC: Support S22 series
    - Improve [ADB] Check SU
    - Improve [ADB] Disable/Enable OTA: Update for more variant
    - Improve [ADB] Delete bloatware: Add some Verizon bloatware
    - Fix bugs
    - Security update

    Salu2
    I managed to bring back the *#0*# by connecting usb and running the SamFW FRP tool and under MTP there is an option to enable secret codes for VZW and thats what fixed it. Now I can get back into the menu to be able to change to another CSC.
    1
    Hi guys, i can't enter to diagnosis mode *#0*#. There are other methods to enter to this?
    There is a new version, everything works
    https://samfw.com/blog/samfw-frp-tool-1-0-remove-samsung-frp-one-click
  • 3
    Small update: I've contacted Samsung regarding the CSC change, and they will be conducting a small remote session to see if users can change the CSC locally, without all the samkey ****ery.

    Not just that, but turns out Three (and possibly other carriers in the UK) are actively changing the CSC of devices they sell - all UK/European devices should be getting a new CSC called EUA (which does not seem to exist on the Fenrir servers, so there's no firmware using it as of now), and in Samsung's systems, my phone is registered with this CSC, however I can clearly see in DL mode that mine is actually H3G/XEU/H3G (XEU because I have a Vodafone HU SIM card in my phone as well).

    Hopefully I will be given a method to change the CSC, and future requests should go a bit smoother.
    3
    I did this method and it worked https://androidmore.com/change-csc-samsung/

    I have a s21 ultra exynos , and a unlock phone , global version

    I installed the AUT update via odin and the csc was TPA , so i did the method on the link to change to AUT and it worked but it deleted everything
    This method not work on Android 11 / 5G devices
    3
    CSC files are found in the firmware files.
    Download the firmware for BTU and extract it
    That's... Not how it works.

    Most firmware released by Samsung is multi-CSC, specific for the region. Even if you download a BTU firmware via samloader/Frija/etc., it will be an OXM ROM, which contains dozens of CSCs.

    The CSC selection on a Samsung device is pretty straightforward, it's based on three factors: the device's manufacturing CSC code (this, you can change with Samkey), the SIM card's MCC/MNC (Mobile Country Code and Mobile Network Code, basically what defines the SIM card's country of origin and network it is tied to), and the ROM's available CSC images.

    1. First the phone will try to load a carrier CSC. If the manufacturing CSC code is carrier-specific, that will be loaded REGARDLESS of the SIM card inserted. If it's a country-specific CSC code (so, unlocked device bought from Samsung/3rd party retailer in that specific country), then the SIM card's MNC-defined carrier specific CSC will be loaded.
    2. If no carrier specific CSC can be loaded, the phone will try to load a country-specific CSC. First try is for the manufacturing CSC code - even if it's a carrier-specific one, a country is attached to it, so it will try to load that (e.g. a XEU phone bought from EE UK, will try to load BTU, the generic unlocked UK CSC in this step). If that cannot succeed, a CSC based on the MCC of the SIM card will be loaded.
    3. If no country-specific CSC could be loaded, the device will relegate to loading the default CSC of the firmware flashed

    The problem with this is that Samsung provides NO SINGLE-CSC FIRMWARE anymore. You can flash a BTU firmware on a XEU device, but that's actually an OXM firmware that contains both BTU and XEU, and such, XEU will be loaded. So you'd need to flash a firmware that matches your device model, from another region, which in this case will apply that firmware's default CSC, which often ends up with e.g. loss of mobile connectivity, limited WiFi bands, and so on.

    So no, flashing a BTU firmware on an already OXM-flashed device won't suddenly set the CSC to BTU, for that you'd need to access the engineering menu via *#272*[IMEI]# - which does not work on newer firmwares.
    2
    Hi.

    Activation for verizon doesn't work in the latest version?
    I don't have that model but in the changelog it says that you can activate the function again.

    Big Update v.3.0 12/7/2022

    - Add [MTP] Enable secret code (*#06#, *#0*#,...) for Verizon phone
    - Add [TestMode] Disable Factory mode
    - Fix [MTP] Read information: show FAIL on some device
    - Fix [DLM] Read information: a small error
    - Improve [TestMode] Change CSC
    - Improve [ADB] Get list supported CSC: Support S22 series
    - Improve [ADB] Check SU
    - Improve [ADB] Disable/Enable OTA: Update for more variant
    - Improve [ADB] Delete bloatware: Add some Verizon bloatware
    - Fix bugs
    - Security update

    Salu2
    I managed to bring back the *#0*# by connecting usb and running the SamFW FRP tool and under MTP there is an option to enable secret codes for VZW and thats what fixed it. Now I can get back into the menu to be able to change to another CSC.
    2
    @carlitobahsoun

    Is there another way than samkey to change my DBT CSC to ATO? voLTE isn't working with my simcard if I don't have ATO as CSC :/
    till now , only samkey .....
    i dont have volte in my country , no 5g in my country , no google pay in my country , no samsung pay in my country , no PayPal in my country , no paid app or watchface appears in galaxy store in my country , bad bad bad .